Power Line Communication Noise Filtering Circuit Design
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Solution Overview
Problem
Conventional PLC devices face challenges in miniaturization and high production costs due to the need for high current resistant elements in switching units, which are costly and bulky, while also struggling with noise interference that affects network signal quality.
Innovation Solution
A PLC device with a noise detecting and filtering circuit that uses a low current resistant relay and a coupling transformer to separate power and noise signals, allowing for effective noise detection and filtering without allowing power signals to pass through the noise detecting circuit, enabling the use of low current resistant components to reduce product size and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high current resistant switching unit is used to control power signal and network signal passage, then the reliability of signal transmission is improved, but the device size and production cost increase
Solution Approach 1:
The patent divides the switching function into two separate circuits: a noise detecting circuit that handles only noise signals (allowing small relay) and a power signal circuit that handles power and network signals (using filtering unit). This segmentation allows each component to be optimized for its specific function, enabling the use of a small relay in the noise detecting circuit while maintaining overall system reliability
Solution Approach 2:
The patent introduces a coupling transformer as an intermediary component between the power signal circuit and the noise detecting circuit. The transformer isolates the high current power signal from the noise detecting circuit while still allowing noise signals to be detected, enabling the use of low current resistant relays in the noise detecting circuit
2Reliability
If a high current resistant switching unit is used to control power signal and network signal passage, then the reliability of signal transmission is improved, but the production cost increases
Solution Approach 1:
The patent divides the switching function into two separate circuits: a noise detecting circuit that handles only noise signals (allowing small relay) and a power signal circuit that handles power and network signals (using filtering unit). This segmentation allows each component to be optimized for its specific function, enabling the use of a small relay in the noise detecting circuit while maintaining overall system reliability
Solution Approach 2:
The patent replaces the expensive high current resistant relay with a combination of a cheap low current resistant relay and an inexpensive filtering unit. The relay in the noise detecting circuit only needs to handle small noise signals, allowing the use of a much cheaper relay component while the filtering unit handles the power signal protection function
3Reliability
If noise filtering is always applied in the power line, then the network signal quality is improved, but the ability to detect and adapt to noise sources is lost
Solution Approach 1:
The patent makes the noise filtering dynamic by introducing a controllable relay in the noise detecting circuit that can switch between connected and disconnected states. When disconnected, the filtering unit filters noise from the network signal. When connected, the relay allows noise signals to pass through to the detecting module for detection and analysis. This dynamic switching enables the system to adapt between noise filtering and noise detection modes based on operational needs
4Device complexity
If a relay is used in the noise detecting circuit without isolating power signals, then the noise detection function is simplified, but the relay must be high current resistant increasing size and cost
Solution Approach 1:
The patent introduces a coupling transformer as an intermediary component between the power signal circuit and the noise detecting circuit. The transformer isolates the high current power signal from the noise detecting circuit while still allowing noise signals to be detected, enabling the use of low current resistant relays in the noise detecting circuit
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances noise filtering, increases network signal quality, and allows for a more competitive product by reducing production costs and enabling miniaturization of the PLC device.
Implementation Method 1
The other type of element is a coupling transformer which is used to isolate the power signal from the noise detecting circuit and induce the noise generated in the power signal by the load to the noise detecting circuit
Data Source
AI summary
The present invention is to provide a PLC device having noise detecting and filtering functions, which includes a power receiving port having one end connected to a power supply unit for receiving a power signal and a network signal; a noise filtering circuit having one end connected to the other end of the power receiving port for filtering noise of the power signal passing therethrough; a power output port connected between the other end of the noise filtering circuit and a load; a noise detecting circuit having two ends connected to a line between the first filtering unit and power receiving port and a line between the first filtering unit and power output port, respectively; and a processing unit connected to a line between the first filtering unit and power receiving port for receiving the network signal from the noise detecting circuit and transmitting the same to a network apparatus.